@override
Widget build(BuildContext context) {
  return Scaffold(
    body: CustomScrollView(
      slivers: [

        ///头部
        SliverToBoxAdapter(
          child: Container(color: Colors.blue, width: ScreenUtils.screenWidth, height: 200,),
        ),

        // SliverList(
        //   delegate: SliverChildBuilderDelegate(
        //         (context, index) {
        //           return Container(color: index % 2 == 0 ? Colors.yellow : Colors.red, height: 55,);
        //         },
        //     childCount: 20,
        //   ),
        // ),

        ///列表
        SliverGrid.builder(
          gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 1, mainAxisExtent: 55,),
          itemBuilder: (BuildContext context, int index){
            return Container(color: index%2 == 0 ? Colors.red: Colors.yellow,);
          },
          itemCount: 20,
        ),

        ///尾部
        SliverToBoxAdapter(child: Container(color: Colors.blue, width: ScreenUtils.screenWidth, height: 200,),),

      ],
    ),
  );
}